Correlation of flow cytometric and microdensitometric DNA content analysis in lung cancer

The DNA histograms of 29 histologically verified primary lung cancers were analyzed with flow cytometry and microdensitometry. Fresh tumor tissues were imprinted on the slide and air dried for modified Feulgen staining. Then the smears were scanned with a scanning microdensitometer at a wavelength of 550 nm. The S-phase fraction value was estimated from the DNA histogram with a cumulated probability scale. The remaining parts of the tumors were minced and prepared for dispersal as a single cell suspension for propidium iodide staining. The tumor cells were then analyzed with a flow cytometer at 488 nm. The correlation between the analyses measured with these two methods showed r = .75 for the DNA index, r = .71 for the S-phase fraction and r = .61 for the G0G1 population; P < .001. The DNA indices, S-phase fraction values and G0G1 populations obtained with flow cytometry and microdensitometry correlated well.